Where computer equipment such as a general purpose personal computer (hereinafter abridged to PC) is used to remotely control electronic equipment such as a video disk player (hereinafter abridged to VDP) or a video tape player, an interface device desirably couples both devices, which differ in input/output conditions, and allows the computer to instruct each individual operation of the electronic equipment.
If a PC and a VDP, for example, are employed as the above-mentioned computer and electronic equipment, respectively, and if each individual operation of the VDP is instructed by the PC, it is possible to program-control the VDP using a memory included in the PC, and the applicable sphere of the VDP is favourably expandable to the fields of game and education. Therefore, several interface devices of this type have been marketed.
A PC operable as the computer is organized generally as shown in FIG. 1. In this drawing, symbol 1 is a central processing unit (CPU), 2 is a memory, 3 is a keyboard section, 4 is a printer interface (I/F), 5 is CRT I/F, 6 is an RS-232C I/F, 7 is a cassette I/F, and 8 is a system bus line mutually connecting the sections 1 to 7 and including an expandable input-output (I/O) port 8a. Printer I/F 4 has a printer parallel port 4a comprising eight-bit parallel data or control signal lines accommodated to the Centronics Standards, and CRT I/F 5 has a RGB output (component) 5a and a video output (composite) 5b. RS-232C I/F 6 is accommodated to a certain standard for serial transfer and has a serial port 6a which will be coupled via a coupler to a telephone network when the exchange of communications is desired with another PC through the telephone network. Further, cassette I/F 7 has a cassette input 7a and a cassette output 7b.
On the other hand, a VDP operable as the above-noted electronic equipment is constructed so that the individual operations of its VDP main section are switched by the manipulation of its VDP manipulator known as a remotely controlled (hereinafter abridged to remocon) commander. Thus, the VDP manipulator has a transmitter for selecting and transmitting remocon codes according to individual manipulations, and the VDP main section has a receiver for receiving the remocon code and for judging the contents of a command instruction of the former, respectively. The transmitter and receiver are composed of transmitting and receiving ICs forming a pair.
As described above, the PC does not have a standard port to connect a VDP as peripheral equipment, and the VDP is constructed so as to be remotely controlled by a certain remocon code. Therefore, in the case of coupling a PC and a VDP which differ in input/output conditions as described above, an interface device is needed.
A conventional VDP-PC interface device is constructed so that data transfer with the PC is effected through the serial port 6a of the RS-232C I/F 6 which transmits serial data and individual control signals from the PC. One example thereof is shown in FIG. 2. In this drawing, 9 is a parallel-serial decoder having an RS-232C serial port 9a, which alters serial data and individual control signals being input into port 9a from the PC into parallel data and sends the same to a CPU 10. CPU 10 decodes the input data on the basis of a program stored in a memory 11 and generates a remocon code receivable and discriminatable by the VDP. This remocon code is, after being current-amplified by an amplifier 12, sent out by driving an infrared-radiation diode 13a of a transmitter 13. A receiver of the VDP is used to receive this remocon code and control the individual operations thereof.
A conventional interface device of this type handles only signals for remote-controlling video equipment, thus, pictures represented by the video signals of the computer equipment and video equipment are displayed on CRT devices of the respective equipment.
Therefore, when a game or educational program was executed by the computer equipment, for instance, and if the pictures explaining the contents of the game or program were presented on the video equipment, a process input of the computer equipment was displayed on the video equipment, and the processed results were displayed on the computer equipment, the display was executed individually on two CRT devices, thus making viewing difficult.
As described above, the conventional interface device is constructed, in view of unified standards, so that the RS-232C serial port 6a of the PC is employed to output a remote code for the VDP. Thus, it is necessary to alter serial data into parallel data, resulting in a complicated construction and, inevitably, a high cost system. Further, some of the general purpose PCs currently sold in Japan are not provided with RS-232C ports and need external options to operate satisfactorily, resulting in further costs.